1. Field of the Invention
The present invention relates to image capture apparatus, such as a digital camera, that encrypts captured image data and stores the encrypted data in a recording medium.
2. Description of the Related Art
Conventionally, a digital camera that encrypts and stores captured image data has been realized. In a case of data encryption, an encryption key is required to encrypt plain text data. Further, a decryption key is required to decode the encrypted data. An encryption key and a decryption key can be identical depending on an encryption method. Therefore, it is necessary to securely manage either or both of an encryption key and a decryption key, so that the keys are not leaked out to a third party.
An effective method for securely managing the above-described keys is to use an IC (integrated circuit) card which is difficult to be decoded by software or hardware. Japanese Patent Application Laid-Open No. 2001-320668 discusses a digital camera that confidentially stores key data in a storage device such as an IC card and encrypts digital data using the key.
When a key data is read out from a storage device that stores the key data, it is necessary to perform an authentication procedure between the storage device and a digital camera. Authentication prevents a false digital camera that spoofs the digital camera from obtaining key data stored in the storage device. That is, it is required that only the digital camera that knows the correct authentication process can obtain key data, and a third party that does not know the correct authentication procedure cannot obtain key data.
Since a digital camera needs to communicate with a storage device in performing an authentication procedure, some processing time is required.
In a conventional digital camera, after a power switch is turned on, an authentication procedure is started, and an image can be captured only after the authentication procedure ends. Therefore, if a user uses a digital camera that encrypts a captured image, the user needs to wait while an authentication procedure is performed after turning on a power switch before capturing an image. As a result, a user may lose a photo opportunity.
Moreover, a user of a conventional digital camera which encrypts a captured image cannot confirm process steps and result of the authentication procedure. Consequently, an error can occur in which a digital camera stores captured data without performing encryption as desired by a user, due to a failure in loading a device or the like. Further, an error can occur in which a digital camera encrypts a captured image that a user did not wish to encrypt.